Intermittent offshore transfer systems are used to transfer fluids, especially hydrocarbons, between a vessel that repeatedly sails to and away from the system, and a pipeline that has a stationary pipe end lying at the sea floor. In one example, a transfer system is used in the production of hydrocarbons from an undersea reservoir, to transfer hydrocarbons passing from the reservoir along the pipeline up to the sea floor, up to the vessel. The vessel sails away to take the hydrocarbons to a distant location, offloads the hydrocarbons, and then returns for more. In this example, the undersea reservoir is small enough that it is not economical to set up a large production system, or this system has been set up as an early production system to produce hydrocarbons until a larger system is installed. In another example, a transfer system is used in the offloading of a vessel that has tanks that store hydrocarbons, to transfer the hydrocarbons to a pipeline that extends to an onshore refinery or to an onshore hydrocarbon gas distribution system. In either example, prior art transfer systems have included a fixed or anchored body to which the vessel is moored and to which the vessel is connected by a conduit, or the transfer system includes anchor chains and a conduit that both can be picked up by the vessel. A transfer system that minimized the setup procedure and the time required to set up a vessel so fluid transfer can begin, would be of value.
A deep water hydrocarbon loading system, described in U.S. Pat. No. 5,041,038, minimizes the setup procedure and time required, by providing a single pickup member that is attached to a group of conduits and a group of chains, so only one heavy member must be picked up and attached to the ship. All chains and conduits still must be initially installed in the sea, and each must be connected to the vessel. This results in a considerable cost to initially install the system, and the setup procedure for an arriving vessel is still complicated and time consuming.